Yup, some 802.11 wireless "hotspot" networks block port 25 as well. Very annoying. My personal workaround to this is to have a personal server tucked away at a colo facility, which among other things, runs a SMTP server listening on port 2025 (to get around the port 25 blocking insanity). This SMTP server will relay e-mail on my behalf, no matter when I am in the Internet, after my laptop uses STARTTLS and AUTH to authenticate myself to my SMTP server.
May I add running this through SSH? That is what I do. All my outgoing SMTP and incoming POP is through SSH to my home server, protecting me from such nefarious operations.
I even found one 802.11 hotspot (WISPer), that did not have the SSH port blocked and I could have done all my work without paying (did anyway, as I want to encourage hotspot deployments).
